Catalysts based on crystalline aluminosilicate

ABSTRACT

A catalyst is described based on crystalline aluminosilicates of the pentasil type, characterized by the fact that it is constructed from primary crystallizes with an average diameter of at least 0.01 μm and less than 0.1 μm, that are combined to at least 20% to agglomerates of 5 to 500 μm, in which the primary crystallites or agglomerates are bonded together by finely divided aluminum oxide, that its BET surface is 300 to 600 m 2 /g and its pore volume (determined according to mercury porosimetry) is 0.3 to 0.8 cm 3 /g, that it is present in H form and that the amount of finely divided aluminum oxide binder is 10 to 40 wt. %, referred to the total weight of the aluminosilicate, in which the finely divided aluminum oxide binder is present in the reaction charge as peptizable aluminum oxide hydrate, sodium aluminate being used as aluminum and alkali source, and primary synthesis of the crystalline aluminosilicate occurs without addition of acid. A method is also described for production of such a catalyst and its preferred applications.

[0001] The invention concerns catalysts based on crystallinealuminosilicates of the pentasil type.

[0002] Catalysts based on crystalline aluminosilicates produced from asource of aluminum, a source of silicon, a source of alkali, a template(for example, a tetrapropylammonium compound) and water are known fromU.S. Pat. No. 3,702,886.

[0003] Production of methanol conversion catalysts based on crystallinealuminosilicates is known from DE-A-28 22 725. The diameter of theprimary crystallites is 1 μm and more. Production of primarycrystallites with diameters well above 1 μm is aimed at. For thispurpose, crystal growth must be promoted by higher temperatures andnucleus formation inhibited by low concentrations of the templateessential for crystallization of zeolites. In addition, there is nomention of the use of binders or the size of the agglomerates

[0004] According to DE-A-24 05 909 (FR-A-2 217 408), catalysts forhydrocarbon conversion are produced based on zeolites of the ZSM-5 type,in which the average diameter of the primary crystallites lies in therange from 0.005 to 0.1 μm. Agglomerates on the order of 0.1 to 1 μm areproduced from the primary crystallites. To produce catalysts, theagglomerates are mixed with aluminum oxide as binder, among otherthings, but in which other binders are mentioned as equivalent. Nocomments are found concerning the particle size of the binder. Inaddition, synthesis was conducted in the presence of sulfuric acid,using Al₂(SO₄)₃×H₂O.

[0005] According to DE-A-29 35 123. ZSM-5 or ZSM-11 zeolites areprepared, using ammonium hydroxide and an alcohol as template, in whichthe presence of nuclei is characteristic. The zeolites are used ascracking and hydrocracking catalysts and as catalysts for isomerizationand dewaxing. Aluminum oxide can be used as binder. However, there areno comments concerning the size of the primary crystallites or of theagglomerates and binder.

[0006] A method for production of zeolites and their use as catalystsfor conversion of aliphatic compounds to aromatic hydrocarbons isdescribed in DE-A-29 13 552. A mixture of butanol and ammonium hydroxideis used as template. The size of the primary crystallites is supposed tobe less than 3 μm, preferably less than 2 μm. A lower limit is notstated. Aluminum oxide, among others, can be used as binder for theagglomerate, but in which no particle sizes are mentioned for theagglomerates and binder.

[0007] A method for production of large flat-structured crystals ofzeolites of the pentasil type from SiO₂ and a compound of one or moretrivalent elements, like Al, B, Fe, Ga, Cr, in amine-containingsolutions is known from DE-A-35 37 459, characterized by the fact thathighly dispersed SiO₂, prepared by burning of a silicon chloridecompound, is used as starting material. The zeolites are used forconversion of organic compounds, especially for conversion of methanolto hydrocarbons containing lower olefins and aromatics. The obtainedzeolites are not agglomerated.

[0008] EP-A-173 901 concerns a method for production of small zeolitescrystallites of the ZSM-5 type with an SiO₂/Al₂O₃ molar ratio of one in5, corresponding to an Si/Al atomic ratio of more than 2.5. The smallestdimension of the crystallites is below 0.3 μm. The crystallites aresubjected to an ion exchange reaction and, after mixing with a matrixmaterial, are formed into larger particles. These are dried andcalcined, obtaining catalysts for different hydrocarbon conversionreactions. No comments are found concerning the type and effect of thematrix material.

[0009] EP-A-123 449 describes a method for conversion of alcohol orethers to olefins, using zeolites catalysts treated with steam; thesehave a crystal size of less than 1 μm and can be incorporated in amatrix. Clay, silica and/or metal oxide are mentioned as matrixmaterials.

[0010] U.S. Pat. No. 4,206,085 concerns hydrocarbon conversion catalystsbased on zeolites and a matrix material to increase abrasion resistance.Aluminum oxide from pseudoboehmite and SiO2 from ammonium polysilicateor silica sol is used as matrix material. The preferred zeolites belongto the faujasite type. No comments are made concerning the size of thezeolites crystals.

[0011] U.S. Pat. No. 4,025,572 concerns a method for production ofspecific hydrocarbon mixtures, in which the catalyst bed containszeolite, among other things. Synthesis of the zeolite is run in thepresence of sulfuric acid, using Al₂(SO₄)₃×H₂O. According to oneexample, the zeolite catalyst is mixed with 90 wt. % aluminum oxide andpelletized.

[0012] EP 0 362 364 A1 concerns catalysts based on crystallinealuminosilicates of the pentasil type with an Si/Al atomic ratio of atleast 10, constructed from primary crystallites with an average diameterof at least 0.1 μm and, at most, 0.9 μm. The size of the primarycrystallites is considered important for the lifetime of the catalyst.The same applies for EP 0 448 000 A1. A methanol to olefin process andan olefin to diesel process are mentioned as application examples.

[0013] The task underlying the invention, in contrast, is to preparecatalysts based on crystalline highly active aluminosilicates thatexhibit increased activity and selectivity with very good lifetime, incatalytic processes, especially in the CMO (conversion of methanol toolefin) process or methanol to propylene (MTP) conversion processes andolefin to olefin (OTO) processes.

[0014] This task is solved by the catalysts according to Claim 1.

[0015] It was surprisingly found that both excellent lifetime andexcellent selectivity and activity of the catalysts according to theinvention result precisely at an average particle size of the primarycrystallites of the crystalline aluminosilicates in the range betweenabout 0.01 and less than 0.1 μm with maintenance of the other featuresaccording to Claim 1.

[0016] If the primary crystallites are combined partly intoagglomerates, they are only loosely bonded to each other, as in a fillercake, for example. The primary crystallites can be recovered relativelyeasily from this, for example, by dispersion of the filter cake in anaqueous medium and by agitation of the dispersion.

[0017] It is important that the primary crystallites have an averagediameter of at least 0.01 μm and less than 0.1 μm. The average diameterof the primary crystallites preferably lies in the range from 0.01 to0.06 μm. Particularly good results are obtained, if the average diameterof the primary crystallite lies in the range from 0.0 15 to 0.05 μm. Ifthe average diameter is less than 0.01 μm, both the activity andlifetime of the catalysts are substantially reduced. The averagediameter of the primary crystallites is defined as the arithmetic meanbetween the largest and smallest diameters of an individual crystallite,averaged over a number of crystallites, determined by scanning electronmicroscopic investigations at a magnification of 80,000 (see below).This definition has meaning in crystallites with an irregular crystalhabit, for example, in rod-like crystallites. In spherical or roughlyspherical crystallites, the largest and smallest diameters coincide.

[0018] The stated values for the primary crystallites are averagedimensions (arithmetic mean from the largest and smallest dimensions,averaged over a number of crystallites). These values are determinedwith an LEO field emission scanning electron microscope (LEO ElectronMicroscopy, Inc., USA) by means of powder samples of the catalysts,redispersed beforehand in acetone, treated with ultrasound for 30seconds and then applied to a support (probe current range: 4 pA to 10nA). Measurement occurs at 80,000-fold magnification. The values couldbe confirmed at 253,000-fold magnification.

[0019] The primary crystallites or agglomerates are bonded to each otherby finely divided aluminum oxide, which is preferably obtained byhydrolysis of organoaluminum compounds.

[0020] The composites generally have dimensions from 20 to 1000 μm,especially 50 to 800 μm. These values are also average dimensions,defined as mentioned previously.

[0021] It was surprisingly found that when the primary crystallite sizejust defined is maintained, particularly good catalysts are obtainedaccording to Claim 1, if the finely divided aluminum oxide binder ispresent in the reaction charge as a peptizable aluminum oxide hydrate,and the amount of aluminum oxide binder, referred to the total weight ofthe end product (catalyst) is at least 10 wt. % and does not exceedabout 40 wt. %.

[0022] At least 95% of the particles of the peptizable aluminum oxidehydrate (referred to average diameter) are preferably less than or equalto 55 μm. The finely divided aluminum oxide binder is preferablyobtained by hydrolysis of aluminum trialkyls or aluminum alcoholates.

[0023] The structure of the catalysts from primary crystallites,agglomerates and binder particles also determines the BET surface,determined according to DIN 66131 (300 to 600 m²/g), the pore volume,determined according to the mercury porosimetry method according to DIN66 133 (0.3 to 0.8 cm³/g), as well as the pore diameter, i.e., at least10%, preferably at least 20%, and especially at least 60%, of the porespreferably have a diameter from 14 to 80 nm.

[0024] The BET surface, the pore volume and pore diameter represent anoptimal choice, in order to obtain catalysts with high activity,selectivity and lifetime.

[0025] The catalyst according to the invention is preferablycharacterized by the fact that it is obtained as follows:

[0026] (a) an alkaline aluminosilicate gel is produced in known fashionin an aqueous reaction charge containing a silicon source, an aluminumsource, an alkali source and a template at elevated temperature andoptionally elevated pressure, and converted to a crystallinealuminosilicate, but during which the reaction is interrupted when theobtained primary crystallites have an average diameter of at least 0.01μm, but less than 0.1 μm, preferably from 0.01 to 0.06 μm, especiallyfrom 0.015 to 0.05 μm;

[0027] (b) the primary crystallites are separated from the aqueousreaction medium as preagglomerates, dried and subjected to intermediatecalcining;

[0028] (c) the product from stage (b) is convened with aproton-containing substance, or one that yields protons when heated, forexchange of the alkali ions in an aqueous medium, separated, dried andsubjected a lain to intermediate calcining, whereupon an agglomeratefraction of about 5 to 500 μm is separated:

[0029] (d) the agglomerate fraction from stage (c) is mixed with thefinely divided aluminum oxide hydrate;

[0030] (e) the product from stage (d) is subjected to final calcining.

[0031] The significance of the individual stages, according to which thecatalyst according to the invention is obtained, is further explainedbelow:

[0032] In stage (a), an aqueous reaction charge containing a siliconsource (for example, colloidal silica or an alkali silicate), an alkaliand an aluminum source (alkali aluminate, especially sodium aluminate)and a template is initially produced.

[0033] It was surprisingly found that particularly advantageouscatalysts, especially for OTO and CMO or MTP methods, can be produced,when an alkali aluminate is used, especially sodium aluminate, as alkaliand aluminum source. No (separate) acid addition occurs according to theinvention in stage (a) (primary synthesis of the crystallinealuminosilicate). In particular, in comparison to known methods, nomineral acids, like sulfuric acid, are used in the reaction chargeduring primary synthesis. The problems that arise during handling of(strong) acids are avoided and advantageous catalysts are obtained.

[0034] If the catalyst is to be used according to a particularlypreferred variant of the invention in a CMO or MTP process, especially aprocess according to DE 100 27 159 A1, whose disclosure in this respectis included in the present description, the weight fractions betweensilicon source and aluminums source are chosen so that crystallinealuminosilicates with an Si/Al atomic ratio between about 50 and 250,preferably about 50 and 150. especially about 75 to 120, are obtained.

[0035] If the finished catalyst according to another particularlypreferred variant of the invention is prescribed for use in an OTOprocess, especially a process according to DE 100 00 889 A1, whosedisclosure in this respect is included in the present invention, theweight fractions between the silicon source and the aluminum source arechosen so that crystalline aluminosilicates with an Si/Al atomic ratiobetween about 10 and 100, preferably between about 20 and 65, especiallyabout 20 to 50, are obtained.

[0036] An alkaline aluminosilicate gel is produced in known fashion fromthe reaction charge at elevated temperature and optionally elevatedpressure. One can operate even at temperatures of 90° C., but in thiscase the reaction times are relatively long (about 1 week). It istherefore preferable to operate at temperatures from 90 to 1 90° C.,especially from 90 to 150° C., in which an overpressure is automaticallyestablished as a function of temperature at temperatures of more than100° C. (under normal conditions).

[0037] During the reaction, the aluminosilicate gel is converted to acrystalline aluminosilicate. If the temperature of the reaction chargeis higher than 190° C., growth of the aluminosilicate primarycrystallites is too rapid and unduly large primary crystallites areeasily obtained, while aluminosilicate gel is still present in thereaction charge.

[0038] Tetralkylammonium compounds, preferably tetrapropyl ammoniumhydroxide (TPA OH) or tetrapropylammonium bromide (TPABr) are used astemplates. Mixtures of ammonia or an organic amine and another organiccompound from the group of alcohols, preferably butanol, can also beused as template.

[0039] The aqueous reaction charge for stage (a) preferably has a pHvalue from 10 to 13. At a pH value of less than 10, conversion of thealuminosilicate gel to the crystalline aluminosilicate runs relativelyslowly. At higher pH values than 13, the aluminosilicate crystals canredissolve in some cases.

[0040] Formation of the crystalline aluminosilicate primary crystallitescan be controlled by appropriate choice of the silicon source, thealuminum source, the alkali source and the template, as well as byappropriate selection of the temperature and pH value and the mixingspeed. It is essential that the reaction be interrupted, when theobtained primary crystallites have an average diameter of at least 0.01μm and less than 0.1 μm, preferably in the range from 0.01 to 0.06 μmespecially from 0.015 to 0.05 μm.

[0041] Several test charges are run for this purpose. Even after a fewattempts, the optimal parameters can be determined, based on which therequired size range of the primary crystallites is obtained. Anindication of termination of the reaction also consists of the fact thatthe pH value of the reaction charge rises abruptly.

[0042] According to the invention, a new reaction charge need not beproduced in each case. Instead, the silicon source, the alkali source,the aluminum source, the template and the water from the mother liquorsof previous syntheses can be used to produce the aluminosilicate gel andmade up by the amounts of the mentioned compounds required for synthesisof the aluminosilicate gel.

[0043] Formation of the aluminosilicate primary crystallites from stage(a) occurs preferably at a pH value between 10 and 13, at which thereaction charge is agitated. In this manner, the size distribution ofthe primary crystallites is homogenized. The agitation speed, however,should preferably be no more than 900 rpm. At higher agitation speeds,the percentage of smaller primary crystallites is higher, which might beadvantageous, if it is guaranteed that the average diameter of allprimary crystallites is at least 0.01 μm.

[0044] In stage (b), the primary crystallites are separated from theaqueous reaction medium as preagglomerate, i.e., not as individualcrystallites. This is preferably achieved by adding a flocculent to theaqueous reaction medium. A cationic organic macromolecular compound isgenerally used as flocculent.

[0045] The flocculent facilitates not only separation of the primarycrystallites from the reaction medium (improved filterability), but alsomeans that the primary crystallites are combined into preagglomerates,which are essentially the same as the agglomerates formed in thesubsequent stage in terms of size, structure and addition of primarycrystallites. The preagglomerates are dried and subjected tointermediate calcining, which is initially preferably conducted in aninert atmosphere at about 200 to 350° C., especially at about 250° C.,during which part of the template is desorbed.

[0046] Intermediate calcining can then be completed in an oxidizingatmosphere at about 500 to 600° C., in which any residual amount oftemplate still present is burned off.

[0047] The preagglomerates are generally subjected to intermediatecalcining for about 1 to 20 hours in the inert atmosphere and about 1 to30 hours in the oxidizing atmosphere.

[0048] In stage (c), the product from stage (b) is converted with aproton-containing substance, or one that yields protons when heated, forexchange of the alkali ions in aqueous medium. For example, ion exchangecan be conducted by means of a dilute mineral acid (for example,hydrochloric acid or sulfuric acid) or an organic acid (for example,acetic acid). Ion exchange preferably occurs by agitation for at leastone hour at temperatures between 25 and 100° C., at least part of thealkali ions in the preagglomerates of the primary crystals beingexchanged by hydrogen ions. If necessary, ion exchange can be repeatedunder the same conditions.

[0049] After exchange of the alkali ions in the aqueous medium, theproduct containing protons (H-zeolite) is separated (for example, byfiltration), dried and subjected to intermediate calcining again.Intermediate calcining is conducted at temperatures from 400 to 800° C.,preferably at about 600° C. over a period from 5 to 20 hours.

[0050] Instead of dilute acid, ion exchange can also be conducted withan ammonium salt solution under comparable conditions. In this case, thealkali ions are exchanged by ammonium ions. If the product so obtainedis subject to intermediate calcining, ammonia is eliminated and aproduct containing protons is obtained.

[0051] The product obtained after intermediate calcining containsagglomerates, on the one hand, that are ≧500 μm, and, on the other hand,dust fractions that are ≦5 μm. An agglomerate fraction of about 5 to 500μm is therefore separated.

[0052] This agglomerate fraction is mixed in stage (d) with the finelydivided aluminum oxide hydrate, at least 95% of which is preferably ≦55μm and at least 30%≧35 μm. These values are referred in each case to theaverage diameter, averaged over a number of crystallites, which isdefined like the average diameter of the primary crystallites. Inparticular, the aluminum oxide typically has the following particlespectrum.

99%≦90 μm

95%≦45 μm

55%≦25 μm.

[0053] The aluminum oxide hydrate is essentially responsible foradjustment of the pore volume of the catalyst according to theinvention. The amount of finely divided aluminum oxide hydrate binderaccording to the invention is about 10 to 40 wt. %, referred to thetotal weight of the product (the mixture) of stage (d).

[0054] The finely divided aluminum oxide hydrate binder is preferablypeptizable aluminum oxide, which is particularly low in Na and Fe.

[0055] It was surprisingly found that a significant improvement incatalytic properties of the catalysts according to the invention isobtained, if an acid concentration from 0.15 to 2.5 mol H⁺/mol Al₂O₃,preferably from 0.20 to 1.5 mol H⁺/mol Al₂O₃, and especially 0.4 to 1.0mol H⁺/mol Al₂O₃, is set for peptization of the aluminum oxide hydrate.

[0056] Peptization can be conducted, in principle, with organic orinorganic acids in a concentration range of the acid from 0.1 to 100%.For example, organic acids. like 100% acetic acid, or dilute inorganicacids, like 52% nitric acid, etc., can be used.

[0057] The product from stage (d) is subjected to final calcining. Thiscan generally be conducted at temperatures between about 500 and 850° C.for 1 to 12 hours. However, it was surprisingly found in the context ofthe present invention that final calcining is conducted with particularadvantage at a temperature from 660 to 850° C. for less than 5 hours,especially from 680° C. to 800° C. for 1 to 4 hours. With thisrelatively short final calcining, at elevated temperatures, the acidityof the acid centers of the catalysts can obviously be advantageouslyinfluenced and, at the same time, the stability of the catalystaccording to the invention increased. It was also found that thisadvantageous “intensified”final calcining exhibits positive effect onthe catalytic properties of the catalysts based on aluminosilicate evenin other aluminosilicate catalysts, when other (arbitrary) aluminum,alkali and silicon sources are used and arbitrary templates, as well asbinders not according to the invention.

[0058] The so obtained end product, as already mentioned, can be usedwith particular advantage in CMO or MTP and OTO processes. However, inprinciple, use in other hydrocarbon conversion reactions, especiallyolefin to diesel (COD) methods, dewaxing methods, alkylations,conversion of paraffin to aromatic compounds (CPA), as well as relatedreactions, is not ruled out.

[0059] The invention is further explained by the followingnon-restricting examples.

Comparative Example 1

[0060] A catalyst was prepared according to example 1 of EP 0 369 364 B]with an average diameter of the primary crystallites of about 0.3 μm(Si/Al ratio 105). The method and physical and chemical properties ofthe product stated there are expressly included in the presentdescription by reference.

[0061] Aluminosilicate zeolites with a primary crystallite size of <1 μmwere produced according to this comparative example. The catalysts wereproduced using aluminum oxide as binder. The detailed procedure was asfollows:

[0062] A reaction mixture was produced by intimate mixing of twosolutions at room temperature in a 40 liter autoclave. The two solutionswere referred to as solution A and solution B. Solution A was producedby dissolving 2218 g TPABr in 11 kg deionized water. 5000 g of acommercial silica was introduced to the solution. Solution B wasprepared by dissolving 766 g NaOH and then 45.6 g NaAlO₂ in 5.5 litersof deionized water. The still warm solution B was added to solution A.The autoclave was then closed and brought to reaction temperatureimmediately with agitation of about 60 rpm. After about 50 hours, thereaction was completed, as was apparent from the pH jump. After cooling,the autoclave was opened, the product removed from the reaction vesseland filtered. The filter cake was suspend in 40 liters of deionizedwater, mixed with about 5 liters of a 0.5 wt. % aqueous suspension of acommercial flocculent and decanted after agitation and settling of thepreagglomerate of the solid. The described washing process was repeateduntil the wash water had a pH value of 7 to 8 and a Br concentration ofless than 1 ppm. The suspension, in which preagglomerates of primarycrystallites were apparent, which were obviously held together by theflocculent, was filtered. The filter cake was then dried for 12 hours at120° C.

[0063] The dried filter cake was ground with a commercial granulator toa particle size of 2 mm.

[0064] The granulator was brought to 350° C. at a heating rate of 1°C./min under nitrogen (1000 Nl/h) and calcined at 350° C. for 15 hoursunder nitrogen (I 000 Nl/h). The temperature was then raised to 540° C.at a heating rate of 1° C./min and the granulate calcined for 24 hoursat this temperature in air, to burn off the remaining TPABr.

[0065] The calcined Na zeolite was suspended in a 5-fold amount of a 1 maqueous HCl solution and brought to 80° C. It was agitated for an hourat this temperature. About 1 liter of a 0.4 wt. % suspension offlocculent was then added and the supernatant acid was decanted offafter settling of the solid. The procedure so described was repeatedagain.

[0066] The solid, in about 10 washing processes, was suspended in eachcase in 60 liters of deionized water under agitation and mixed with anaverage of 100 mL of 0.4 wt. % suspension of flocculent. After settlingof the zeolite, the supernatant solution was decanted. When the Cl⁻content in the wash water was <5 ppm, the suspension was filtered offand dried for 15 hours at 120° C.

[0067] The dried H-zeolite was ground with a commercial granulator to 2mm and brought to 540° C. under air at a heating rate of 1° C./min andcalcined at this temperature in air for 10 hours.

[0068] 5000 of the calcined H-zeolite was ground by means of alaboratory mill to a particle size of about 500 μm and mixed in a doubleZ kneader with 1470 g of a commercial peptizable aluminum oxide hydratewith a particle size spectrum of 98 wt. %≦90 μ: 95 wt. %≦45 μm and 55wt. %≦25 μm dry for 15 minutes. 4565 mL of a 1.5 wt. % aqueous aceticacid solution (for peptization of the aluminum oxide hydrate) and 417 mLsteatite oil were slowly added to this mixture.

[0069] This mixture was kneaded for about 30 minutes to plastificationand extruded in a commercial extruder to molded articles with a diameterof about 1.5 mm and a length of about 3 mm. Final calcining wasconducted at 650° C. for 3 hours.

[0070] The analysis values and physical and chemical properties of theproduct are shown in Table 1.

Comparative Example 2

[0071] A catalyst was prepared according to example 4 of DE-A-24 05 909,but in which no treatment with nickel nitrate, i.e., no Ni exchange,occurred. The production method and physical and chemical properties ofthe product, stated in DE-A-24 05 909 under example 4, are expresslyincluded in the present description by reference.

Example 1

[0072] A catalyst was prepared as described in comparative example 1,conversion being interrupted as soon as the average particle diameter ofthe primary crystallites was at 0.03 μm. Calcining and ion exchange alsooccurred according to comparative example 1.

Example 2

[0073] A catalyst was prepared as described in example 1. in which theratio of SiO₂ and NaAlO₂ was varied with the same total molarity ofthese compounds., so that the Si/Al ratio of the catalyst was at 31.Conversion of the reaction mixture was interrupted as soon as theprimary crystallite diameter was 0.03 μm.

[0074] The physical and chemical properties of the catalyst, as comparedto example 1 and of examples 1 and 2, were summarized in Table I. TABLEI Vergleiche- Beispiel beispiel 1 1 2 Molverhaltnis Ausgangs- stoffeSiO₂ 100 100 100 NaAlO₂ 0.67 0.67 2.21 NaOH 23 23 23 TPABr 10 10 10 H₂O1100 1100 1100 kristallisationsdaten Temperature (° C.) 130 130 130 Zeit(h) 50 23 29 Kristallinitat (%) 100 100 100 Primarkristallitgrobe 0.30.03 0.03 (μm) Phys. und chem. Eigen- schaften des Katalysators Si/AlAtomverh. 105 105 31 BET-Oberflache (m²/g) 366 385 393 Porenvolumen(cm²/g) 0.51 0.46 0.55 Poren ≧ 80 nm (%) 21.1 20.7 8.2 Poren 14-80 nm(%) 68.0 69.2 77.3

[0075] Headings

EXAMPLES Comparative Example 1

[0076] Left

[0077] Molar ratio initial substances

[0078] Crystallization data

[0079] Temperature

[0080] Time

[0081] Crystallinity

[0082] Primary crystalline size

[0083] Physical and chemical properties of the catalyst

[0084] Si/Al atomic ratio

[0085] BET surface

[0086] Pore volume

[0087] Pores ≧80 nm

[0088] Pores 14-80 nm

Application Example

[0089] This application example demonstrates the advantages of thecatalyst according to the invention with reference to catalytic data ofthe CMO process (conversion of methanol to olefins) in an isothermalfixed bed reactor.

[0090] The experiments were run as in practical example 1 of EP 0 369364, whose disclosure in this respect is included in the presentdescription by reference. To summarize, the methanol/water feed (1 g/1g) with an LHSV of 1 (1/(1×h)), i.e., liter of total feed per liter ofcatalyst and per hour, was passed over 300 cm³ CMO catalyst in anisothermal fixed bed tubular reactor at a pressure of 1 bar afterpassing through an isothermal fixed bed tubular reactor for partialconversion of methanol to dimethyl ether. Conversion of methanol wasmaintained at almost 100%. At a specified value (conversion EOR, %), thereaction was interrupted and the catalyst regenerated.

[0091] The gas phase and liquid phase at the output of the CMO catalystreactor were determined with the usual gas chromatographic analysismethods. The distribution of hydrocarbons is summarized in Table II,together with other relevant data. TABLE II Vergleichs- Vergleichs-Katalysator beispiel 1 beispiel 2 Beispiel 1 Bindemittel AluminiumoxidAluminiumoxid Aluminiumoxid Primarkristallitgrobe 0.3 0.05-0.07 0.03(μm) Temperature (° C.) 400 415 395 Druck (bar) 1 1 1 LHSV (l/l × h) 1 11 MeOH/H₂O (g/g) 1 1 1 Dauer 1. Zyklus (h) 927 548 1000 abgebr. Dauer 2.Zyklus (h) 2000 abgebr. 415 2000 abgebr. 1. Zyklus Mittelwerte (Gew. %)C₁-C₄ Paraffine 10.5 9.1 9.9 C₃-C₄ Olefine 51.9 50.8 60.8 C₃ Olefin 24.822.3 34.4 C₅ ⁺Gasolin 37.6 40.1 29.3 Konversion EOR (%) 99.7 99.5  100abgebr. 2. Zyklus Mittelwerte (Gew. %) C₁-C₄ Paraffine 7.5 9.8 9.0 C₂-C₄Olefine 54.8 48.0 63.8 C₃ Olefin 26.2 19.9 36.1 C₅ ⁺Gasolin 37.7 42.227.2 Konversion EOR (%)  100 abgebr. 98.4  100 abgebr.

[0092] Headings

[0093] Catalyst

Comparative Example 1 Comparative Example 2 Example 1

[0094] Left

[0095] Binder

[0096] Primary crystallite size

[0097] Temperature

[0098] Pressure

[0099] LHSV

[0100] MeOH/H₂O

[0101] Duration of 1^(st) cycle

[0102] Duration of 2^(nd) cycle

[0103] 1^(st) cycle average value (wt. %)

[0104] C₁-C₄ paraffin

[0105] C₂-C₄ olefin

[0106] C₃ olefin

[0107] C₅ ⁺ gasoline

[0108] Conversion EOR

[0109] 2^(nd) cycle average value (wt. %)

[0110] C₁-C₄ paraffin

[0111] C₂-C₄ olefin

[0112] C₃ olefin

[0113] C₅ ⁺ gasoline

[0114] Conversion EOR

[0115] Other columns

[0116] abgebr.=interrupted

[0117] EOR=end of run;

[0118] Table II clearly shows the improved selectivity of the catalystaccording to example 1 in production of C₂-C₄ olefins, as well as thevery good lifetime of the catalyst according to the invention. Thecatalysts (also the catalyst according to the invention) wereregenerated after completion of the first cycle, in which the MeOHstream was initially shut off. Nitrogen was then supplied to drive outthe remaining MeOH. Finally, oxygen in gradually higher concentrationswas added to the nitrogen, in order to burn off the hydrocarbonsdeposited on the catalysts. The temperature of the catalysts was alwayskept below 480° C. Regeneration of the catalysts was completed when theoxygen content of the nitrogen stream at the input and output of thecatalyst bed was the same.

[0119] It should also be noted that the catalyst according to example 1exhibits higher conversion values at 395° C. than the comparativecatalysts that revere tested at higher temperatures.

[0120] It was also surprisingly found that the selectivity of thecatalyst according to the invention in the production of C₂-C₄ olefins,as well as its lifetime, could also be significantly raised by runningpeptization of the employed aluminum oxide hydrate with an increasedacid concentration of more than about 2.0 mol H⁺/mol Al₂O₃. Theaforementioned properties of the catalysts according to the inventioncould also be further improved by shortened final calcining, conductedat higher temperatures (for example, 700° C. for 3 hours).

[0121] During use of other comparative catalysts that had either anSi/Al ratio or a primary crystallite size outside of the values statedin Claim 1, it was found that the selectivity for propylene is muchlower than during use of the catalyst according to example 1.

1. Catalyst based on crystalline aluminosilicates of the pentasil type,characterized by the fact that it is constructed from primarycrystallites with an average diameter of at least 0.01 μm and less than0.1 μm, which are combined to at least 20% to agglomerates of 5 to 500μm, the primary crystallites or agglomerates being bonded together byfinely divided aluminum oxide, that its BET surface is 300 to 600 m²/gand its pore volume (determined according to mercury porosimetry) is 0.3to 0.8 cm³/g, that it is present in H form, and that the amount offinely divided aluminum oxide binder is 10 to 40 wt. %, referred to thetotal weight of the aluminosilicate and binder, in which the finelydivided aluminum oxide binder is present in the reaction charge as apeptizable aluminum oxide hydrate, in which sodium aluminate is used asaluminum and alkali source and the primary synthesis of the crystallinealuminosilicate occurs without addition of acid.
 2. Catalyst accordingto claim 1, characterized by the fact that (a) the catalyst, if it is tobe used for a method for conversion of methanol to olefins, especiallypropylene, has an Si/Al atomic ratio of about 50 to 250, preferablyabout 50 to 150, especially about 75 to 120, or (b) the catalyst, if itis to be used for an olefin to olefin conversion, has an Si/Al atomicratio between 10 and 100, preferably between about 20 and 65, especiallyabout 20 and
 50. 3. Catalyst according to claim 1 or 2, characterized bythe fact that the average diameter of the primary crystallites lies inthe range from 0.01 to 0.06 μm, especially from 0.015 to 0.05 μm. 4.Catalyst according to one of the preceding claims, characterized by thefact that final calcining is conducted at a temperature between 500° and850° C. for 1 to 12 hours, preferably from 660 to 850° C. for less than5 hours, especially 680° C. to 800° C. for 1 to 4 hours.
 5. Catalystaccording to one of the preceding claims, characterized by the fact thatan acid concentration of 0.15 to 2.5 mol H⁺/mol Al₂O₃, preferably 0.20to 1.5 mol H⁺/mol Al₂O₃, and especially 0.4 to 1.0 mol H⁺/mol Al₂O₃, isset for peptization of the aluminum oxide hydrate.
 6. Catalyst accordingto one of the preceding claims, characterized by the fact that at least10%, preferably at least 20%, especially at least 60%, of the pores havea diameter from 14 to 80 nm.
 7. Catalyst according to one of thepreceding claims, characterized by the fact that at least 95% of theparticles of the peptizable aluminum oxide hydrate are ≦55 μm (referredto average diameter).
 8. Catalyst according to one of the precedingclaims, characterized by the fact that the finely divided aluminum oxidebinder is obtained by hydrolysis of aluminum trialkyls or aluminumalcoholates.
 9. Catalyst according to one of the preceding claims,characterized by the fact that is obtained as follows: (a) an alkalinealuminosilicate gel is produced in known fashion in an aqueous reactioncharge containing a silicon source, an aluminum source, an alkali sourceand a template at elevated temperature and optionally elevated pressure,and converted to a crystalline aluminosilicate, but during which thereaction is interrupted when the obtained primary crystallites have anaverage diameter of at least 0.01 μm and less than 0.1 μm, preferably inthe range from 0.01 to 0.06 μm, especially from 0.015 to 0.05 μm; (b)the primary crystallites are separated from the aqueous reaction mediumas preagglomerates, dried and subjected to intermediate calcining; (c)the product of stage (b) is converted with a proton-containingsubstance, or one that yields protons when heated, for exchange of thealkali ions in an aqueous medium, separated, dried and subjected againto intermediate calcining, whereupon an agglomerate fraction of about 5to 500 μm is separated; (d) the agglomerate fraction from stage (c) ismixed with the finely divided aluminum oxide hydrate; (e) the productfrom stage (d) is subjected to final calcining.
 10. Catalyst accordingto one of the preceding claims, characterized by the fact that toproduce the aluminosilicate gel, the silicon source, the alkali source,the aluminum source, the template and the water from the mother liquorsof the previous synthesis are used and made up by the amounts of theinvention compounds necessary for synthesis of the aluminosilicate gel.11. Catalyst according to one of the preceding claims, characterized bythe fact that the template is tetrapropylammonium hydroxide (TPAOH) ortetrapropylammonium bromide (TPABr).
 12. Catalyst according to one ofthe preceding claims, characterized by the fact that the template is amixture of ammonia or an organic amine and another organic compound fromthe group of alcohols, preferably butanol.
 13. Catalyst according to oneof the preceding claims, characterized by the fact that the aqueousreaction charge from stage (a) has a pH value from 10 to 13 andformation of the aluminosilicate primary crystallizes occurs duringagitation at 90 to 190° C., preferably at 90 to 150° C.
 14. Catalystaccording to one of the preceding claims, characterized by the fact thatthe agitation speed is a maximum of 900 rpm.
 15. Catalyst according toone of the preceding claims, characterized by the fact that the primarycrystallites in stage (b) are separated from the aqueous reaction mediumby addition of a flocculent.
 16. Catalyst according to one of thepreceding claims, characterized by the fact that intermediate calciningin stage (b) is conducted in an inert atmosphere at about 200 to 350°C., preferably about 350° C., and then in an oxidizing atmosphere atabout 500 to 600° C., in order to burn off any remaining amount oftemplate still present.
 17. Catalyst according to one of the precedingclaims, characterized by the fact that intermediate calcining in stage(c) is conducted at 400 to 800° C., preferably about 540° C., over aperiod from 5 to 20 hours.
 18. Method for production of a catalystaccording to one of the preceding claims, comprising the process stepsa) to e) according to claim
 9. 19. Use of the catalyst according to oneof the claims 1 to 17 in an MTP or OTO process, preferably according toDE 100 27 159 A1 or DE 100 00 889 A1.